The correct answer is auditing.
Accounting is the process of recording, classifying, summarizing, and reporting financial information. Bookkeeping is the process of recording financial transactions. Auditing is the process of reviewing and verifying financial statements.
Accounting starts where bookkeeping ends because accounting takes the information that is recorded in the books and uses it to create financial statements. Auditing begins where accounting ends because auditing takes the financial statements and reviews them to make sure that they are accurate and complete.
The other options are incorrect because they are not related to the process of accounting. Certification is the process of verifying that someone has the knowledge and skills to perform a particular job. Stock is a type of security that represents ownership in a company. Purchase is the act of buying something.